A liquid crystal display panel used in a liquid crystal display device such as a liquid crystal television receiver does not emit light itself. Therefore, a backlight device is required as a separate lighting device. Such a backlight device is arranged behind the liquid crystal display panel (i.e., on an opposite side from a display surface). A backlight device including a plurality of linear light sources and a diffuser plate arranged on a side to which light emitted from the linear light sources is directed is known (see Patent Document 1).    Patent Document 1: Japanese Published Patent Application No. 2006-208968